Microbiome Analysis: Trends in Cancer Epidemiology, Challenges and Opportunities

Analysis of microbiome sampled from a given cancer site can yield information that may serve as a prognostic of exposure, risk, disease progression, and treatment response. We reviewed available published literature, and grants funded by the National Cancer Institute's Division of Cancer Control and Population Sciences to identify trends and areas for future research. The incorporation of microbiome analysis in epidemiologic studies of cancer is providing some promising insights into risk stratification. However, our analysis identified several knowledge gaps in this emerging field: 1. Limited evidence for the stability of different biospecimen types over time and at given temperatures for microbiome analysis, 2. Analysis software that reliably standardizes sequencing data from different platforms and corrects for biases against rare or unrepresented taxa, 3. Harmonization of methods used for microbiome analysis across research centers. 4. Surrogate markers that will be useful for monitoring disease progression from the time of infection to cancer development, 5. Time-varying microbiome in the natural history of different cancers in order to identify key microbiota or shifts in community structure, and 6. Determining whether the microbiota cause or effect cancer risk and outcomes. If these knowledge gaps are addressed, microbiome analysis is likely to provide the cancer field with new approaches for early diagnosis and help develop more effective preventative measures.